This invention relates to a fragrance controlled release device constructed from a silicone elastomer and/or a silicone pressure sensitive adhesive. The devices may be attached to household and industrial substrates in one embodiment, and in another embodiment may include colognes and perfumes where the device is intended to be adhered to human skin as a substrate for releasing fragrances, colognes, and perfumes into the environment about the skin rather than into the skin.
Odor modification is the intentional change of one odor by the addition of another more acceptable odor. Air fresheners, perfumes, and industrial deodorants typify odor modifiers, in that they employ fragrance materials for odor control by altering a malodor to a more pleasant character or to an acceptable level. Among the most serious effects of malodors are coughing, headache, nausea, irritation of mucous membranes, and shortness of breath. The need for control of such effects is obvious in locations such as nursing homes, hospitals, restaurants, houses, automobiles, boats, and in the work-a-day environment. Malodors that must be combatted are human body odor, cigarette smoke, toilet odors, and the odor of cooking foods, for example. Generally, the control of body odor is by means of colognes and perfumes, whereas fragrances containing products are employed for industrial and household applications. The prior art is replete with delivery systems for fragrances, colognes, and perfumes. Exemplary systems for the application of fragrances and air fresheners locally or into the immediate environment are sprays, aerosols, sticks, daps, liquid creams and lotions, atomizers, cellulosic and paper matrices. One method developed for timed or controlled release is by means of matrix devices in which a solute to be delivered is compounded in a matrix, generally a polymer such as cellulose esters, polyvinylchloride, polytetrafluoroethylene, polypropylene, polycarbonate, polyethylene, polystyrene, and nylon, which may be in the form of a flat sheet. The solute agent is then released from the matrix by diffusion, and the rate of release decreases with time and is not constant and is typified by first order release kinetics. A relatively constant release rate, characterized by zero order release kinetics, can be achieved by means of depot or reservoir devices in which the rate controlling membrane encloses a cavity that contains the active solute ingredient. The reservoir provides substantially constant solute activity until the solute is exhausted by diffusion. However, the controlled release devices of the prior art suffer from the disadvantage that the duration of fragrance release is limited, often requiring many daily as well as many weekly applications in order to insure the activity of these products. In contrast, the present invention provides new delivery methods and improved controlled release devices for sustaining the release of fragrances, colognes, and perfumes. In published unexamined European Patent Application No. 0186146A2, dated July 2, 1986, of Japan Liquid Crystal Co., Ltd., it is stated that the direct addition of perfume to a synthetic resin compound is not practical or effective because the perfume is volatile, liable to denature, and unstable to heat, so that it is difficult to mold a mixture of perfume and a synthetic resin into a desired shape. The patentee therefore forms an inclusion compound of a perfume in cyclodextrin, powders and dries the inclusion compound, and mixes the powder with the synthetic resin to form products. While the patentee mentions silicone resin as a synthetic resin, products of silicone resin containing perfume are not disclosed, rather the silicone resin is employed with the inclusion compound of cyclodextrin, liquid paraffin, and benzotriazole, to produce semi-conductor substrates exhibiting rust preventative, mold-mildew proofing, or antifungal effects. In accordance with the present invention, however, improved and unexpected results are obtained contrary to such teachings and in the absence of the necessity of pre-forming the perfume into an inclusion composition for later formulation into a resin. In another published unexamined European Patent Application No. 0218891A2 dated April 22, 1987, of Union Camp Corporation, a silicon rubber being a cross-linked silicone elastomer of the type vulcanized at room temperature is used in the construction of an elongated hollow cylindrical body member that includes a chamber containing about fifty grams of a volatile liquid fragrance that is intended to be diffused through the cylinder walls and into the atmosphere. A companion application no. 0218892A2 used the same silicone rubber material but in the shape of a closure member for a glass container holding about fifty grams of volatile liquid fragrance which diffuses into the atmosphere through the silicone elastomer closure member. In the U.S. Pat. No. 4,600,146, dated July 15, 1986, to Shin-Etsu Chemical Col, Ltd., a polymeric material such as an organopolysiloxane is formed into a capillary tube that is wire reinforced and filled with fragrance material which diffuses into the atmosphere through the walls of the tube. While these devices utilize silicone materials for diffusion of fragrances into the atmosphere, the devices are cumbersome to handle and expensive to manufacture, and are complex in design in comparison to the simple multi-laminate patch type of fragrance releasing elements of the present invention. Laminate-type systems are known as in U.S. Pat. No. 4,638,043, issued Jan. 20, 1987, in which heat liable drugs are released from a polyurethane matrix that has been light cured rather than heat cured so as not to inactivate the drug. Such a device differs from the present invention in that it is limited to drugs or therapeutic agents, and as a transdermal delivery system, infuses therapeutic agents into the skin, whereas the devices of this invention release fragrances in the opposite direction. Further, the present invention relies upon heat to cure some matrix materials which would otherwise inactivate a system of the type described in U.S. Pat. No. 4,638,043, and in a specific embodiment, includes an impermeable layer for preventing interaction of the fragrance with the skin, which would render devices of the type in U.S. Pat. No. 4,638,043, inoperative. Except for the inclusion of heat curable matrix materials, the same differences exist between the devices of the present invention and those depicted in U.S. Pat. No. 4,655,767, issued Apr. 7, 1987. Further, in the latter patent an impermeable foil or polymer covers the elastomeric drug releasing body whereas in the device of this invention the outer layer is permeable to the fragrance to be released. In U.S. Pat. Nos. 4,703,070, and 4,725,575, issued Oct. 27, 1987, and Feb. 16, 1988, respectively, silicone rubber matrices are disclosed similar to those employed herein. However, in the former patent a compatabilizing agent is required, and neither teach the particulars of the multi-laminate layers employed herein especially the rate controlling outer layer, and the impermeable inner layer which prevents interaction of fragrance with the skin and has utility for individuals otherwise allergic to a particular fragrance due to irritant reaction or skin sensitivity.